Bibcode
Vicente, B.; Garzón, F.; Cabrera-Lavers, A.
Referencia bibliográfica
Stellar Clusters & Associations: A RIA Workshop on Gaia. Proceedings. Granada, Spain, May 23 - 27, 2011. Edited by: Alfaro Navarro, E. J.; Gallego Calvente, A. T.; Zapatero Osorio, M. R., pp.393-394
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2011
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Descripción
The luminosity function is not only crucial to know stellar density
distribution in space, and thus to know the structure of the Galaxy, but
it allows the determination of the stellar mass function using the
mass-luminosity relationship. The luminosity function and mass function
are fundamental to the understanding of star formation and the evolution
of the Milky Way. It is customary to assume that the luminosity function
in the solar neighbourhood, which can be obtained directly from precise
star counts, well represents that of the Galactic disk, if not over the
whole Galaxy and external galaxies of similar morphological type. Under
this assumption, we simply need to calculate in the solar vicinity and
then move it to the disk area of interest. In this regard, the larger
the sample used for the determination the more reliable the
extrapolation to galactic studies. We have determined the luminosity
function in the solar neighbourhood up to 200 pc considering the proper
motions as distance estimators. We used the parameter "reduced proper
motion" (Luyten [1938]) for calibration of the apparent magnitudes to
absolute ones. This calibration must be done with kinematically similar
populations, i.e., they share the same velocity distribution. So, prior
to calculating the luminosity determination we used the SKY model
(Wainscoat et al. [1992]) to separate stars with different kinematic
evolution in our catalogue. As our kinematical database, we used the
CdC-SF Catalogue (Vicente et al. [2010]), which has proper motion
precision similar to that of Hipparcos but up to much fainter magnitudes
(V = 15). Such a rich data allow getting the luminosity function for
distances greater than those identified so far by extending existing
results. Having stars at greater distances implies that we can get
information covering the bright field of the luminosity function. Also,
a larger sample with smaller proper motions produces a luminosity
function that is more adapted to the real Galaxy model thanks to a
smaller correction factor.